EVALUATION OF AN AUTOMATED MALARIA PARASITE BLOOD SMEAR READING DEVICE

Open Access
Author:
Abdalla Mohamed, Azah M
Graduate Program:
Public Health Sciences
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
None
Committee Members:
  • Vernon Michael Chinchilli, Thesis Advisor
Keywords:
  • READING DEVICE
  • BLOOD SMEAR
Abstract:
ABSTRACT Accurate identification and quantification of malaria parasites in a timely manner are critical in measuring treatment outcomes. Microscopy is widely used as the “gold standard” method for detecting and quantifying malaria species. However, the method is time consuming. Automated devices have been developed, such as that developed by World Health Technologies (WHT) for a malaria parasite blood smear reader, but have not been thoroughly validated. The objective of this research was to evaluate the WHT automated device through comparison with microscopy. A crude assessment of the sensitivity and specificity was based on the presence or absence of malaria parasite using a set of blood smear slides standardized according to the World Health Organization (WHO), (n= 55), which consists of patient derived slides, 20 of which are positive for malaria, 20 are negative for malaria and 15 are plasmodium falciparum positive control slides. In addition 150 blood smear slides of unknown status were available from the Household Survey in Equatorial Guinea. Each slide was analyzed by the microscopy and for all positive slides, the particular species were determined. A square-root transformation of the counts was calculated prior to the comparison of methods. For the WHO slides, the WHT device resulted in 88.6% sensitivity (For the Household Survey slides, sensitivity was 100% (95% CI = 0.75-1.00) and specificity was 94% (95% CI = 0.90-0.99). The findings showed different results regarding the sensitivity and specificity performance of the WHT device between the WHO slides and Household Survey slides, but they are comparable to the performance of humans. Density values for positive slides were significantly higher for the WHT device compared to microscopy.